Merge rules for whitespace in attribute selectors

[1j01]

Currently if you want no whitespace around the operators, you have to choose two samples with whitespace on one side, even if you can tell what it's referring to with the highlight and option labels.

You'd need to update your data structure to support multiple keys, but the options could be:

• Require whitespace around operators in attribute selectors
• Disallow whitespace around operators in attribute selectors

and if you want to allow all possible options:

• Require whitespace on the right of operators in attribute selectors and not on the left
• Require whitespace on the left of operators in attribute selectors and not on the right

And I guess it would be good for the other whitespace options.